Gearing for elevators



(No Model.) 2 Sheets-Sheet 1..

N. O. BASSETT. GEARING FOR ELEVATORS. No. 485,163. Patented Nov. 1,1892.

(No Model.) 2 Sheets- Sheet 2.

N. U. BASSETT. GEARING FOR ELEVATORS. $10,486,163. Patented Nov. 1,1892.

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WITNESSES- INVENTEJR.

UNrrEE STATES PATENT OFFICE.

NORMAN C. BASSETT, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE THOM-SON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

GEARING FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 485,163, dated November1, 1892.

Application filed October 11, 1890.

To all whom it may concern.-

Be it known that I, NORMAN C. BASSETT, a citizen of the United States,residing at Lynn, county of Essex, and State of Massachusetts, haveinvented a certain new and useful Improvementin Gearing for Elevators,ofwhich the following is a specification.

In the application of electric or other fastrunning motors to thedriving of elevators many difficulties are encountered in providing asimple, effective, and noiseless mechanism for transmitting the powerand reducing the high speed of the motor to the comparativelyslow speedof the car. The present invention aims to overcome these ditficulties bythe use of adifierential rope device for the power-transmittingmechanism, and it diifers from all such previous constructions byrelieving the fast-running diiterential pulley-shaft of the main portionof the load and transferring the same to a comparatively-s10w-runnin gsheave, which arrangement materially reduces the loss from friction andwear upon the powertransmitting mechanism. Other forms ofpower-transmitting mechanism than the differential rope devicespecifically described may be also used, but always in such a way thatthe main portion of the load is divided into two portions balanced upona slow-running sheave, while the power-transmitting mechanism takes onlythe unbalanced por tion of the load, which is only a small proportion ofthe total weight.

My invention is illustrated in the accompanying drawings, wherein--Figure 1 is a side view of one form of structure embodying myimprovements. Fig. 2 is a front view of the same, and Fig. 3 shows amodification difieriug only in certain details of construction.

The elevator-car C is attached to one end of a cable or cables R, whichpass over a sheave or sheaves S, journaled in the usual manner at theupper end of the hatchway, and to the opposite end of this cable isfastened the counter-weight IV. This counterweight will preferably bemade heavy enough to overbalance the car by about one-half the maximumload the elevator is designed to lift, and as the weight of the car isusually as great or greater than that of the load it is de- Serial No.367,835- (No model.)

signed to carry it will be seen that the major portion of the totalload, comprising the car, counter-balance, and load, will be dividedinto two portions, balanced upon the slowrunning sheave S. Since,therefore, the counter-weight overbalances the car by one-half themaximum load the power of the motor is exerted to pull down the car whenit is empty, or, in other words, to raise the counter-weight and to liftthe car when fully loaded; but in either case the capacity of the motorneeds tobe equal only to one-half the maximum load carried by the car.Ordinarily but a comparatively-small proportion of the total load is allthat resists the power-transmitting mechanism and the rapidly-runningparts immediately connected with the electric motor represented at M,which operates the elevator. Of course the total strain exerted by thecar, weight, load, and motor falls upon the sheave S.

Mounted upon the armature-shaftof the motor or driven thereby throughintermediate gearing are the differential drums L L. An endless rope (bywhich term I include also a belt or equivalent power-transmittingconnection) R passes from drum L around pulley S, (shown in Figs. 1 and2,) journaled in hangers upon the counter-weight, thence around drum L,traveling pulley T, and back to drum L. The traveling pulley T isconnected by a rope R with the counter-weight W and passes around apulley M at the bottom of the hatchway, from which is suspended atake-up weight W. This latter weight is provided with pivoted pawls P P,which engage ratchet-bars G G and allow the weight to descend freely totake up any slack in the connections, but prevent upward movement.

The operation of my invention will be ap parent by observing that whenthe drivingdrums are revolved in the direction of the arrow A, Fig. 1,the rope R is wound on drum L faster than it is unwound from L, which 5tends to raise the driving-pulley T, pulling down the counter-weight andlifting the car, while at the same time-the rope is wound off from theother side of L faster than it is wound upon L, which allows thecounter- I00 weight and pulley S to descend at the same rate of speed atwhichT is drawn up. In Fig.

3 the arrangement differs somewhat from that in Figs. 1 and 2, but onlyin details of construction, the principle of operation remaining thesame. The movable pulley S is connected to the bottom of the car by arope R passing around pulleys S S the arrangement of pulley T anddriving-rope R remaining the same as before. This change simply resultsin pulling down upon the car C, rather than liftinguponthe;counter-weightW the resulting movement being the same in eithercase. In both these arrangements it is to be observed that the car andcounterweight are moved positively by the motor in either direction; butthe main balanced portion of the total load comes upon thecomparativeIy-slow-running sheave S, where the loss due to friction is aminimum, while the weight actually bearing upon the differentialdrum-shaft will be equal only to that portion of the total load whichthe motor is called upon to move. It is this transfer of a largeproportion of the total load from the fast to the slow running bearingswhich constitutes the basis of my invention.

I am aware that an elevator car and its counter-weights have beensuspended directly by a differential rope mechanism. I am also awarethat an elevator-car has been counterbalanced and provided with ahydraulic pl unger or other mechanism to move it. I do not claim anysuch devices. Myinvention is confined to an elevator in which the weightof the car is overbalanced, so that the drivingmotor has only to liftthe unbalanced part of the load on the car, the motor being afastrunning one and connected with the car by difierential ropemechanism which reduced the speed.

What I claim is- '1. The combination of the elevator car,counter-weight, slow-running sheave, and cable passing around the sheaveand attached to the car and weight, whereby the main portion of thetotal load divides into two portions balanced upon and carried by saidsheave, with a motor, a fast-running differential drum driven thereby,and a rope power-transmitting mechanism driven by the drums andcommunicating a slow speed to the car, whereby only the unbalancedportion of the total load is brought upon the drum, substantially asdescribed. p

2. The combination of acable passed around a sheave at the upper end ofthe hatchway and the car and counter-weight attached to the oppositeends of the said cable, with a motor, a diiferential drum operated bysaid motor, and rope power-transmitting mechanism driven by said drumand furnishing means for positively moving the said car and weight ineither direction.

3. The combination, with an elevator-car and counter-weight attached tothe opposite ends of a cable passed around a slow-running sheave, asdescribed, of a motor, a differential drum operated by said motor anddriving a rope powertransmitting device connected with thecounter-weight for moving the car and weight, for the purpose set forth.

4:. The combination, with an elevator-car and counter-weight attached tothe opposite ends of a supporting-cable, as described, of a motor and adifferential rope power-transmitting device having two connections withthe counter-weight,and thereby furnishing means for moving the saidweight and car positively in either direction, as described.

5. The combination, with an elevator-car and counter-weight suspended bya cable from a sheave journaled at the upper end. of the hatchway, of anelectric motor, difierential drums driven thereby, the travelingpulleys, and an endless rope passing around said drn ms and pulleys, asdescribed, and thereby furnishing means for moving the said car andweight in either direction.

6. The combination, with an elevator-car, counter-weight, slow-runningsheave, and cable passing around said sheave and attached to the car andcounter-weight, of a motor and intermediate rope power-transmittingconnections adapted to overcome the resistance of the unbalanced portionof the load, and a take-up device for keeping the connections taut,consisting of a weight provided with a pawl, and a rack with which saidpawl engages, as described.

NORMAN O. BASSETT.

Witnesses:

HENRY N. SWEET, JOHN W. GIBBONEY.

